Cefas contract report C2848 Radiological Habits Survey: Hinkley Point, 2010 2011 Environment Report RL 01/11 This page has been intentionally left blank Environment Report RL 01/11 Final report Radiological Habits Survey: Hinkley Point, 2010 F.J. Clyne, C.J. Garrod, P. Rumney, L.M. Hughes and V.E. Ly Peer reviewed by G.J. Hunt Approved for publication by W.C. Camplin 2011 The work described in this report was carried out under contract to the Environment Agency, the Food Standards Agency and the Health and Safety Executive. Cefas contract C2848 FSA Project PAU 198 / Lot 7 / ERI0006 This report should be cited as: Clyne, F.C., Garrod, C.J., Rumney, P., Hughes, L.M., and Ly, V.E., 2011. Radiological Habits Survey: Hinkley Point, 2010. RL 01/11. Cefas, Lowestoft A copy can be obtained by downloading from the Cefas website: www.cefas.defra.gov.uk © Crown copyright, 2011 2 CONTENTS SUMMARY .............................................................................................................................................. 7 1 INTRODUCTION ........................................................................................................................... 11 1.1 Regulatory framework ........................................................................................................... 11 1.2 Radiological protection framework ........................................................................................ 12 2 THE SURVEY ............................................................................................................................... 14 2.1 Site activity ............................................................................................................................ 14 2.2 Survey objectives .................................................................................................................. 14 2.3 Survey areas ......................................................................................................................... 15 Figure 1. The Hinkley Point aquatic survey area .......................................................................... 17 Figure 2. The Hinkley Point terrestrial (outer ring) and direct radiation (inner ring) survey areas .................................................................................................................................. 18 2.4 Conduct of the survey ........................................................................................................... 19 3 METHODS FOR DATA ANALYSIS ............................................................................................. 21 3.1 Data recording and presentation ........................................................................................... 21 3.2 Data conversion .................................................................................................................... 21 3.3 Rounding and grouping of data ............................................................................................. 21 3.4 Approaches for the identification of high rates ...................................................................... 23 3.5 Data quality ........................................................................................................................... 24 4 AQUATIC RADIATION PATHWAYS ........................................................................................... 25 4.1 Aquatic survey area .............................................................................................................. 25 Figure 3. Brean Down ................................................................................................................... 26 Figure 4. Burnham-on-Sea beach ................................................................................................ 27 Figure 5. Stolford beach ............................................................................................................... 28 Figure 6. Kilve beach .................................................................................................................... 30 Figure 7. Blue Anchor beach ........................................................................................................ 31 4.2 Commercial fisheries ............................................................................................................. 31 4.3 Aquatic food wholesalers and retailers ................................................................................. 32 4.4 Hobby fishing, angling, and shellfish collecting ..................................................................... 32 4.5 Wildfowling ............................................................................................................................ 32 4.6 Other pathways ..................................................................................................................... 33 4.7 Food consumption data ......................................................................................................... 33 Table A. Summary of adults’ consumption rates of foods from the aquatic survey area .............. 34 Table B. Summary of children’s consumption rates of foods from the aquatic survey area 35 4.8 Intertidal occupancy .............................................................................................................. 36 Table C. Summary of adults’ intertidal occupancy rates .............................................................. 37 Table D. Summary of children’s intertidal occupancy rates ......................................................... 38 4.9 Gamma dose rate measurements......................................................................................... 39 4.10 Handling of fishing gear and sediment .................................................................................. 39 Table E. Summary of adults’ handling rates of fishing gear and sediment .................................. 40 Table F. Summary of children’s handling rates of sediment ........................................................ 40 4.11 Water based activities ........................................................................................................... 40 5 TERRESTRIAL RADIATION PATHWAYS .................................................................................. 42 5.1 Terrestrial survey area .......................................................................................................... 42 5.2 Terrestrial food wholesalers and retailers ............................................................................. 44 5.3 The transfer of contamination off-site by wildlife ................................................................... 44 5.4 Food consumption data ......................................................................................................... 44 Table G. Summary of adult consumption rates of foods from the terrestrial area ......................... 45 Table H. Summary of children’s consumption rates of foods from the terrestrial survey area ...... 46 3 6 DIRECT RADIATION PATHWAYS .............................................................................................. 47 6.1 Direct radiation survey area .................................................................................................. 47 6.2 Residential activities .............................................................................................................. 47 6.3 Leisure activities .................................................................................................................... 48 6.4 Commercial activities ............................................................................................................ 48 6.5 Occupancy rates ................................................................................................................... 48 Table I. Summary of direct radiation occupancy rates ................................................................. 48 6.6 Gamma dose rate measurements......................................................................................... 49 7 USES OF HABITS DATA FOR DOSE ASSESSMENTS ............................................................. 51 7.1 Combined pathways .............................................................................................................. 51 7.2 Foetal dose assessment ....................................................................................................... 51 7.3 Total dose assessment ......................................................................................................... 51 8 COMPARISONS WITH THE PREVIOUS SURVEY ..................................................................... 53 8.1 Aquatic survey area .............................................................................................................. 53 Table J. Comparison between 2006 and 2010 consumption rates of aquatic food groups for adults ............................................................................................................................................. 54 Table K. Comparison between 2006 and 2010 intertidal occupancy rates and handling rates of fishing gear and sediment for adults .......................................................................................... 55 8.2 Terrestrial survey area .......................................................................................................... 56 Table L. Comparison between 2006 and 2010